Works fine but prefer solid plugs. But works ok.

Did not fit my small batch fermenter. My fault, I didn't pay close attention to the description.

Works great. I like the low profile, plus it catch a little if it bubbles out. I have a few in different sizes. If this is the smaller size they can also be used to fit smaller one gallon jugs ( wine bottles) by putting in hot water for a while and making them soft enough to force in the smaller opening. Once they cool they are permanent. I have always used this style and never needed to tied down my airlocks so they don’t pop out.

It works and fits the Fermonster lid.

The stopper arrived on time and is a perfect fit for the PET carboy that I ordered at the same time.

Excellent so far and I don't expect any issues. I don't use any old rubber bungs anymore. Very pleased.

Fits most every carboy I have. Works great

This rubber is much too firm to seal in a hole that isn't also tapered the exact same way as the stopper. The very thin straight-walled hole in the lid of my 1gal Fermonster did not seal against this hard rubber stopper.I didn't test if it fit my airlocks well.

Perfect fit, easy to use

I have a few misc sized barrels with medium bungs that tend to accept #10 - #10, I started buying these because it was obnoxious to figure out what bung goes where, when these are universal. Also fits my Fermonster just fine. Good to have a couple in the brew house.

The hole in the lid is a size 10 so you need this stopper and it works great with almost any airlock

If you have PET carboys you need a stopper like this or a carboy cap/hood. If you're going to dry hop your beer and/or use a racking cane to transfer these are a little easier to work with. They fit snug and do the job.